Segment Reporting (Parenthetical) (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Segment Reporting Information [Line Items]
Net revenues		$ 3,197,880	$ 2,729,754	$ 6,210,867	$ 5,559,421
Total assets		12,812,635	12,148,499	12,812,635	12,148,499	$ 13,476,879
Behavioral Health Services
Segment Reporting Information [Line Items]
Net revenues	[1]	1,431,497	1,259,123	2,746,834	2,565,232
Total assets	[1]	7,159,426	6,819,694	7,159,426	6,819,694
Behavioral Health Services | Located in U.K.
Segment Reporting Information [Line Items]
Net revenues		172,000	136,000	337,000	273,000
Total assets		$ 1,369,000	$ 1,192,000	$ 1,369,000	$ 1,192,000

[1] Includes net revenues generated from our behavioral health care facilities located in the U.K. amounting to approximately $172 million and $136 million for the three-month periods ended June 30, 2021 and 2020, respectively, and approximately $337 million and $273 million for the six-month periods ended June 30, 2021 and 2020, respectively.  Total assets at our U.K. behavioral health care facilities were approximately $1.369 billion and $1.192 billion as of June 30, 2021 and 2020, respectively.